Ipomoea species are members of the morning glory family Convolvulaceae. Ipomoea batatas, the cultivated species, is commonly produced for consumption and referred to as the white or yellow sweetpotato and the orange yarn. The plants are typically fast growing, green vines possessing a wide variety of leaf shapes ranging from palmate and deeply lobed, to cordate or triangular shaped leaves with no lobes. Ornamental sweetpotatoes, which have been bred and selected for their unique foliage colors, leaf shapes and plant habits, typically do not produce large fleshy storage roots like the sweetpotato cultivated for consumption. In comparison, storage roots produced by ornamental sweetpotatoes are typically not as large because no selection has been exercised for yield, thus storage roots do not begin to swell until very late in the season. Further, the few storage roots that are formed by ornamental sweetpotatoes are typically not as attractive as those produced by the tablestock types as they are generally cracked, very malformed, often mottled in skin and flesh color, and are not palatable.
Late in the growing season when day-lengths begin to shorten or when the plants are stressed, ornamental sweetpotato plants produce tubular flowers that are similar to morning glories, but most plantings are dominated by the appearance of the foliage. The plants are highly desirable due to their ability to grow under varied stress conditions, cover a large space, and last the entire growing season. Moreover, these plants have few insect or disease problems.
Until the release of the Sweet Caroline series of ornamental sweet potatoes (see below) there were six popular types of Ipomoea batatas ornamental sweetpotatoes being cultivated primarily for their annual, summer vines in landscaping applications. These six cultivars are: ‘Blackie’ (not patented), having purple foliage and lavender flowers; ‘Terrace Lime’ (not patented) and ‘Margarita’ (not patented; also known as ‘Sulfur’), which have large brilliant chartreuse leaves and lavender blooms; ‘Black Heart’ (not patented; also known as ‘Ace of Spades’), having heart-shaped leaves with burgundy purple color; ‘Tricolor’ (not patented; also known as ‘Pink Frost’), a variegated plant having pale green, white, and pink-margined leaves; and ‘Lady Fingers’ (unpatented), which has medium green, dainty leaves divided into long, thin, fingerlike lobes that are complemented by burgundy stems and veins.
Ipomoea batatas ‘Margarita’ was recently released in the United States, and has become widely used as a landscape annual. However, it is not suitable for mixed containers as this variety exhibits a very vigorous growth and tends to out-compete other species. See Armitage. A. M. and J. M. Garner, (2001) Ipomoea batatas ‘Margarita’. HortScience 36:178. Another popular variety, ‘Blackie’, is a vigorous purple-leaved clone, which is also unsuited to containerized gardens.
Therefore, to meet the current horticultural demand, it is desirable to produce new, more robust cultivars of ornamental sweetpotato with attractive foliage colors, leaf shapes, and plant architectures. In addition, it would be advantageous to develop cultivars of ornamental sweetpotato exhibiting a more compact growth, and which do not out-compete other species in mixed containers.
Ipomoea batatas ‘Sweet Caroline Light Green’ (U.S. Pat. No. PP15,028, issued Jul. 20, 2004), ‘Sweet Caroline Green’ (U.S. Pat. No. PP15,056, issued Aug. 3, 2004), ‘Sweet Caroline Bronze’ (U.S. Pat. No. PP15,437, issued Dec. 21, 2004), ‘Sweet Caroline Purple’ (U.S. Pat. No. PP14,912, issued Jun. 15, 2004), and ‘Sweet Caroline Red’ (U.S. Pat. No. PP17,483, issued Mar. 13, 2007) are recently introduced cultivars developed at North Caroline State University that are characterized by compact growth habit, moderate to deeply lobed palmate leaves, and attractive foliage color.
The present invention relates to a new and distinct variety of Ipomoea batatas named ‘Sweet Caroline Green Yellow’. This variety is a moderately compact to slightly trailing variety, and it is distinguishable from other varieties by its green foliage with yellow to light yellow variegation, which is not currently available in ornamental sweetpotatoes. The plant has moderate vigor, is moderately to well branched, and is well suited for container production.
Lineage. The Ipomoea batatas ‘Sweet Caroline Green Yellow’ cultivar (breeding designation NC2626-2ORN) is derived from seed of open pollinated ‘Okinawa’ (not patented) collected in Kona, Hi., during November 2002. As a result of being derived from seed resulting from open pollination, the male parent is unknown. The harvested seed was brought to North Carolina State University and assigned the family name NC2626 in the winter of 2003. The family NC2626 contained a total of 68 open pollinated seed. All of these seed were planted in Raleigh, N.C., during Spring 2003. The single, individual plant now known as Ipomoea batatas ‘Sweet Caroline Green Yellow’ was selected in August/September 2003 because of its combination of exceptional features, including its variegation, and has been propagated asexually since that time.
Asexual Reproduction. Since its selection, Ipomoea batatas ‘Sweet Caroline Green Yellow’ has been asexually reproduced at Raleigh, N.C., predominantly by vegetative propagation of vine cuttings. Successively, there have been three cycles of vegetative propagation, one cycle of tissue culture micropropagation, and multiple vegetative propagation cycles to increase the plant population. Asexual reproduction of the new Ornamental Sweetpotato cultivar by cuttings has shown that the unique features of the new cultivar are stable and the plant reproduces true to type in successive generations of asexual reproduction.